The present invention relates generally to feedback systems for improving user control of remotely operated devices. In particular, the invention relates to audible feedback systems utilized in connection with remotely operated power driven manipulators such as "robot arms" and the like.
Remotely operated manipulators are finding wide use in fields ranging from surgery to deep sea exploration in environments ranging from undersea to the surfaces of distant planets. In recent years, the use of remotely controlled manipulator systems to explore undeveloped natural resources has increased dramatically. Remotely operated manipulators are usually employed in hostile or humanly inaccessible environments to make repairs or conduct exploration. Typically, such apparatus includes one or more remotely operated, powered arms which have a terminal device, such as claws, pincers or jaws, which are employed as mechanical analogs of the human hand. The manipulator arms are usually jointed and have several axes of movement. The users of remotely operated manipulators have traditionally monitored manipulator position and motion through the use of closed circuit television. This enables the operator to see the effects of his control inputs in real time and make appropriate adjustments.
Video feedback systems, while very useful, do not provide sufficient information concerning manipulator force. Various schemes exist for providing user feedback information and force, speed, displacement and the like. Many of the prior art systems are analogous to the well-known force feedback devices used to give a natural "feel" to pilot controls on large aircraft which use boosted control systems. Other prior art systems utilize various transducers to sense displacement, speed, and force and use the information derived therefrom to operate a duplicate manipulator which is placed proximately to the operator for direct viewing. An additional system for providing user feedback information on force and speed is disclosed in applicant's co-pending application Ser. No. 466,433, filed Feb. 15, 1983 now U.S. Pat. No. 4,604,559 issued Aug. 5, 1986.
The prior art discloses a number of systems for providing the user with information related to the force, speed, and displacement of the remotely controlled manipulator device. While these systems are highly useful, they do not provide the user with a sense of "touch". The great dexterity of the human hand is heavily dependent upon tactile sensitivity more commonly referred to as the sense of touch. The great importance of the sense of touch in performing delicate tasks can be clearly appreciated by observing the great reduction in dexterity which occurs when the sense of touch is dulled by cold weather or a local anesthetic. A person with very cold hands has unimpaired visual feedback, and can, through the sensing of muscle contraction and tendon displacement, obtain some information relating to manual force exerted in the hand. As is well known, however, a normally dexterous person with very cold hands will find his or her manual dexterity severely impaired due to the lack of tactile feedback from the fingertips and the other surfaces of the hand.
The prior art is noticeably lacking in devices which give the user of remotely operated manipulator devices some semblance of a sense of touch. Force, displacement, and speed feedback information is highly useful but it is not equivalent to a sense of touch. Users of such prior art systems receive little or no information relating to the texture of the objects which are being manipulated. By providing the operator with an intuitively interpretable feedback signal from a tactile transducer mechanically coupled to the manipulator arm itself, the heretofore missing sense of touch is created. This feedback greatly improves controllability of the manipulator arm, especially when used to perform intricate tasks or manipulate delicate materials. The addition of a sense of touch to remote manipulator arm assemblies makes the analogy to a human hand much more complete and the operation of the robot arm can begin to closely approximate the motion and dexterity of a human arm and hand.